How much PSU wattage do I actually need?

Start from the GPU manufacturer's recommended system wattage, then add 20–30% headroom for stability, aging, and future upgrades. Quality matters as much as the number — prefer established 80 Plus certified brands.

Can DDR4 RAM work in a DDR5 motherboard?

No. The slots are physically keyed differently and the standards are electrically incompatible. The motherboard determines which generation you must buy.

Do all CPU coolers fit all cases?

No — every case lists a maximum cooler height, and every radiator size needs matching mounts. Check both before buying, especially for compact cases.

How-ToPublished July 27, 2026· Updated July 29, 2026

How to Choose Compatible Parts for a Custom Desktop Build

Start from the CPU socket, match the motherboard and RAM generation, then check case clearances and PSU wattage with headroom — five checks that prevent nearly every compatibility mistake in a custom PC build.

The short answer

Every compatible build follows the same dependency chain: the CPU decides the socket, the socket decides the motherboard, the motherboard decides the RAM generation, the case decides what physically fits, and the total power draw decides the PSU. Work through those five in order and it is very hard to buy a wrong part.

The five compatibility checks

1. CPU first. Pick the processor for your budget and games, and note its socket (for example AM5 for current AMD Ryzen, LGA1700/LGA1851 for recent Intel). Everything else follows from this choice.

2. Motherboard to match. The board must have the same socket, and its chipset sets your features — memory speeds, number of M.2 slots, USB ports, and overclocking support. Confirm the board supports your exact CPU out of the box or note if a BIOS update is needed. Maxsun boards distributed by Tech Global list supported CPUs on each product page.

3. RAM generation. DDR4 and DDR5 are physically incompatible — a DDR4 stick will not fit a DDR5 board. Match the generation to the board, use two sticks for dual-channel, and check the board's supported speed list.

4. Case clearances. Three numbers matter: maximum GPU length, maximum CPU cooler height, and radiator support if you plan liquid cooling. Compare them against the exact parts you chose — modern GPUs are long, and tower coolers are tall.

5. PSU wattage and connectors. Add up the system's power draw (the GPU maker publishes a recommended PSU wattage — use it), then add 20–30% headroom. Confirm the PSU physically has the PCIe power connectors your GPU needs. A quality 80 Plus unit from FSP, Thermaltake, or Cooler Master protects everything else you just bought.

Common mistakes that slip through

Buying a board that needs a BIOS update for a brand-new CPU — and having no older CPU to flash it with
A tower cooler that blocks the first PCIe slot or does not clear the side panel
A tight PSU with exactly zero headroom — stable today, shutting down after one GPU upgrade
Airflow as an afterthought — in Pakistani summers, an airflow-oriented case and adequate fans are not optional extras

Frequently Asked Questions

The short answer

The five compatibility checks

1. CPU first. Pick the processor for your budget and games, and note its socket (for example AM5 for current AMD Ryzen, LGA1700/LGA1851 for recent Intel). Everything else follows from this choice.

Common mistakes that slip through

Buying a board that needs a BIOS update for a brand-new CPU — and having no older CPU to flash it with

A tower cooler that blocks the first PCIe slot or does not clear the side panel

A tight PSU with exactly zero headroom — stable today, shutting down after one GPU upgrade

Airflow as an afterthought — in Pakistani summers, an airflow-oriented case and adequate fans are not optional extras